RECENT ADVANCES IN SCIENCE 393 



is incorrect and that a certain amount of cyanic acid is produced, 

 varying according to the experimental conditions. The author 

 supports the view recently expressed by Ray, Dey and Ghosh 

 (/. Client. Soc. 191 7, 414) that urea is not attacked by pure 

 nitrous acid alone, but finds that " when a salt of urea is produced 

 by the presence of a sufficiently strong acid, it is immediately 

 attacked by nitrous acid, because an amino-group is thereby 

 presented for such attack." The facts are accounted for by 

 assuming that the constitution of urea in aqueous solution is 

 represented by formula VI. and that in contact with a strong 

 acid it undergoes rearrangement according to the following 

 equation : 



/NH 3 /NH 2 .HX 



HN:C< I +HX = HN:C< 



x O x OH 



VI VII 



The resulting salt VII. then reacts with urea as follows : 



/NH 2 .HX 

 HN : C< + HN0 2 = N a + HNCO + 2 H 2 + HX 



x OH 



The cyanic acid produced is decomposed in two ways as 

 fast as it is produced according to either of the two following 

 reactions : 



HNCO + H 2 = NH 3 + C0 2 

 or HNCO + HN0 2 = C0 2 + N 2 + H 2 



The fact that a certain amount of nitrogen is liable to be 

 fixed in form of an ammonium salt explains why the reaction 

 cannot be made use of for estimating urea in aqueous solution. 



Appended is a list of some other important papers which, 

 for reasons of space, it is not possible to review. 



Cunningham and Dore"e, The Chemistry of Caramel,/. Chem. Soc. 191 7, 589. 

 Fischer and Bergmann, Further Syntheses of Glucosides, etc., Berichte, 19 17, 



50, 711. 

 Komppa and Roschier, Complete Synthesis of Fenchene, Chem. Soc. Abstracts, 



1917,(1), 466. 

 La Forge and HUDSON, Sedoheptose, a New Sugar from Sedum spectabile, 



J. Biol. Chem. 19 17, 30, 61, 

 Pauly, Synthesis of Peptides in the Animal Organism, Zeitsch. physiol. Chem. 



1917,99, 161. 

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